52 resultados para ENANTIOSELECTIVE ADDITION
Resumo:
Some polycyclic aromatic hydrocarbons (PAHs) are ubiquitous in air and have been implicated as carcinogenic materials. Therefore, literature is replete with studies that are focused on their occurrence and profiles in indoor and outdoor air samples. However, because the relative potency of individual PAHs vary widely, health risks associated with the presence of PAHs in a particular environment cannot be extrapolated directly from the concentrations of individual PAHs in that environment. In addition, database on the potency of PAH mixtures is currently limited. In this paper, we have utilized multi-criteria decision making methods (MCDMs) to simultaneously correlate PAH-related health risk in some microenvironments to the concentration levels, ethoxyresorufin-O-deethylase (EROD) activity induction equivalency factors and toxic equivalency factors (TEFs) of PAHs found in those microenvironments. The results showed that the relative risk associated with PAHs in different air samples depends on the index used. Nevertheless, this approach offers a promising tool that could help identify microenvironments of concern and assist the prioritisation of control strategies.
Resumo:
The advantages of bundling e-journals together into publisher collections include increased access to information for the subscribing institution’s clients, purchasing cost-effectiveness and streamlined workflows. Whilst cataloguing a consortial e-journal collection has its advantages, there are also various pitfalls and the author outlines efforts by the CAUL (Council of Australian University Libraries) Consortium libraries to further streamline this process, working in conjunction with major publishers. Despite the advantages that publisher collections provide, pressures to unbundle existing packages continue to build, fuelled by an ever-increasing selection of available electronic resources; decreases in, and competing demands upon, library budgets; the impact of currency fluctuations; and poor usage for an alarmingly high proportion of collection titles. Consortial perspectives on bundling and unbundling titles are discussed, including options for managing the addition of new titles to the bundle and why customising consortial collections currently does not work. Unbundling analyses carried out at Queensland University of Technology during 2006 to 2008 prior to the renewal of several major publisher collections are presented as further case studies which illustrate why the “big deal” continues to persist.
Resumo:
Spaces without northerly orientations have an impact on the ‘energy behaviour’ of a building. This paper outlines possible energy savings and better performance achieved by different zenithal solar passive strategies (skylights, roof monitors and clerestory roof windows) and element arrangements across the roof in zones of cold to temperate climates typical of the central and central-southern Argentina. Analyses were undertaken considering daylighting, thermal and ventilation performances of the different strategies. The results indicate that heating,ventilation and lighting loads in spaces without an equator-facing facade can be significantly reduced by implementing solar passive strategies. In the thermal aspect, the solar saving fraction reached for the different strategies were averaged 43.16% for clerestories, 41.4% for roof monitors and 38.86% for skylights for a glass area of 9% to the floor area. The results also indicate average illuminance levels above 500 lux for the different clerestory and monitor arrangements, uniformity ratios of 0.66–0.82 for the most distributed arrangements and day-lighting factors between 11.78 and 20.30% for clear sky conditions, depending on the strategy. In addition, minimum air changes rates of 4 were reached for the most extreme conditions.
Resumo:
A mathematical model for the galvanostatic discharge and recovery of porous, electrolytic manganese dioxide cathodes, similar to those found within primary alkaline batteries is presented. The phenomena associated with discharge are modeled over three distinct size scales, a cathodic (or macroscopic) scale, a porous manganese oxide particle (or microscopic) scale, and a manganese oxide crystal (or submicroscopic) scale. The physical and chemical coupling between these size scales is included in the model. In addition, the model explicitly accounts for the graphite phase within the cathode. The effects that manganese oxide particle size and proton diffusion have on cathodic discharge and the effects of intraparticle voids and microporous electrode structure are predicted using the model.
Resumo:
This work is concerned with the genetic basis of normal human pigmentation variation. Specifically, the role of polymorphisms within the solute carrier family 45 member 2 (SLC45A2 or membrane associated transporter protein; MATP) gene were investigated with respect to variation in hair, skin and eye colour ― both between and within populations. SLC45A2 is an important regulator of melanin production and mutations in the gene underly the most recently identified form of oculocutaneous albinism. There is evidence to suggest that non-synonymous polymorphisms in SLC45A2 are associated with normal pigmentation variation between populations. Therefore, the underlying hypothesis of this thesis is that polymorphisms in SLC45A2 will alter the function or regulation of the protein, thereby altering the important role it plays in melanogenesis and providing a mechanism for normal pigmentation variation. In order to investigate the role that SLC45A2 polymorphisms play in human pigmentation variation, a DNA database was established which collected pigmentation phenotypic information and blood samples of more than 700 individuals. This database was used as the foundation for two association studies outlined in this thesis, the first of which involved genotyping two previously-described non-synonymous polymorphisms, p.Glu272Lys and p.Phe374Leu, in four different population groups. For both polymorphisms, allele frequencies were significantly different between population groups and the 272Lys and 374Leu alleles were strongly associated with black hair, brown eyes and olive skin colour in Caucasians. This was the first report to show that SLC45A2 polymorphisms were associated with normal human intra-population pigmentation variation. The second association study involved genotyping several SLC45A2 promoter polymorphisms to determine if they also played a role in pigmentation variation. Firstly, the transcription start site (TSS), and hence putative proximal promoter region, was identified using 5' RNA ligase mediated rapid amplification of cDNA ends (RLM-RACE). Two alternate TSSs were identified and the putative promoter region was screened for novel polymorphisms using denaturing high performance liquid chromatography (dHPLC). A novel duplication (c.–1176_–1174dupAAT) was identified along with other previously described single nucleotide polymorphisms (c.–1721C>G and c.–1169G>A). Strong linkage disequilibrium ensured that all three polymorphisms were associated with skin colour such that the –1721G, +dup and –1169A alleles were associated with olive skin in Caucasians. No linkage disequilibrium was observed between the promoter and coding region polymorphisms, suggesting independent effects. The association analyses were complemented with functional data, showing that the –1721G, +dup and –1169A alleles significantly decreased SLC45A2 transcriptional activity. Based on in silico bioinformatic analysis that showed these alleles remove a microphthalmia-associated transcription factor (MITF) binding site, and that MITF is a known regulator of SLC45A2 (Baxter and Pavan, 2002; Du and Fisher, 2002), it was postulated that SLC45A2 promoter polymorphisms could contribute to the regulation of pigmentation by altering MITF binding affinity. Further characterisation of the SLC45A2 promoter was carried out using luciferase reporter assays to determine the transcriptional activity of different regions of the promoter. Five constructs were designed of increasing length and their promoter activity evaluated. Constitutive promoter activity was observed within the first ~200 bp and promoter activity increased as the construct size increased. The functional impact of the –1721G, +dup and –1169A alleles, which removed a MITF consensus binding site, were assessed using electrophoretic mobility shift assays (EMSA) and expression analysis of genotyped melanoblast and melanocyte cell lines. EMSA results confirmed that the promoter polymorphisms affected DNA-protein binding. Interestingly, however, the protein/s involved were not MITF, or at least MITF was not the protein directly binding to the DNA. In an effort to more thoroughly characterise the functional consequences of SLC45A2 promoter polymorphisms, the mRNA expression levels of SLC45A2 and MITF were determined in melanocyte/melanoblast cell lines. Based on SLC45A2’s role in processing and trafficking TYRP1 from the trans-Golgi network to stage 2 melanosmes, the mRNA expression of TYRP1 was also investigated. Expression results suggested a coordinated expression of pigmentation genes. This thesis has substantially contributed to the field of pigmentation by showing that SLC45A2 polymorphisms not only show allele frequency differences between population groups, but also contribute to normal pigmentation variation within a Caucasian population. In addition, promoter polymorphisms have been shown to have functional consequences for SLC45A2 transcription and the expression of other pigmentation genes. Combined, the data presented in this work supports the notion that SLC45A2 is an important contributor to normal pigmentation variation and should be the target of further research to elucidate its role in determining pigmentation phenotypes. Understanding SLC45A2’s function may lead to the development of therapeutic interventions for oculocutaneous albinism and other disorders of pigmentation. It may also help in our understanding of skin cancer susceptibility and evolutionary adaptation to different UV environments, and contribute to the forensic application of pigmentation phenotype prediction.
Resumo:
Shared Services (SS) involves the convergence and streamlining of an organisation’s functions to ensure timely service delivery as effectively and efficiently as possible. As a management structure designed to promote value generation, cost savings and improved service delivery by leveraging on economies of scale, the idea of SS is driven by cost reduction and improvements in quality levels of service and efficiency. Current conventional wisdom is that the potential for SS is increasing due to the increasing costs of changing systems and business requirements for organisations and in implementing and running information systems. In addition, due to commoditisation of large information systems such as enterprise systems, many common, supporting functions across organisations are becoming more similar than not, leading to an increasing overlap in processes and fuelling the notion that it is possible for organisations to derive benefits from collaborating and sharing their common services through an inter-organisational shared services (IOSS) arrangement. While there is some research on traditional SS, very little research has been done on IOSS. In particular, it is unclear what are the potential drivers and inhibitors of IOSS. As the concepts of IOSS and SS are closely related to that of Outsourcing, and their distinction is sometimes blurred, this research has the first objective of seeking a clear conceptual understanding of the differences between SS and Outsourcing (in motivators, arrangements, benefits, disadvantages, etc) and based on this conceptual understanding, the second objective of this research is to develop a decision model (Shared Services Potential model) which would aid organisations in deciding which arrangement would be more appropriate for them to adopt in pursuit of process improvements for their operations. As the context of the study is on universities in higher education sharing administrative services common to or across them and with the assumption that such services were homogenous in nature, this thesis also reports on a case study. The case study involved face to face interviews from representatives of an Australian university to explore the potential for IOSS. Our key findings suggest that it is possible for universities to share services common across them as most of them were currently using the same systems although independently.
Resumo:
There is a mismatch between the kinds of movements used in gesture interfaces and our existing theoretical understandings of gesture. We need to re-examine the assumptions of gesture research and develop theory more suited to gesture interface design. In addition to improved theory, we need to develop ways for participants in the process of design to adapt, extend and develop theory for their own design contexts. Gesture interface designers should approach theory as a contingent resource for design actions that is responsive to the needs of the design process.